In video playing, a symptom that an original video cannot be smoothly decoded or played due to high resolution of the original video and low performance of a user proxy often appears. In addition, if a screen of the user proxy is small and the resolution is low, even if the original video can be decoded smoothly, when finally presented, the decoded image also cannot be presented in the original high resolution due to the restriction of the resolution of the screen. Consequently, visual experience of a high-resolution video is poor and computing resources are wasted.
In a case in which the screen resolution is fixed, using a streaming media server or an image server to transfer a high-resolution video or image causes a waste in network bandwidth or storage space. However, if a low-resolution video is transferred, a mosaic symptom also appears when the video is played, or in particular, enlarged, and therefore viewing of details of pictures is affected.
To solve this problem, a transcoding unit is added between a video source and the user proxy. The transcoding unit transcodes the original video and provides a video in a video format or a resolution that can be supported by the user proxy. Transcoding refers to a process of converting one video coding format to another video coding format, a process of enlarging/reducing a video resolution to another video resolution, or a process in which the preceding two processes are performed at the same time. For example, the transcoding unit may convert an H264-encoding high-definition video into a CIF (Common Intermediate Format; common intermediate format) resolution MPEG (Moving Pictures Experts Group, moving pictures experts group)-4 format video that can be viewed on a mobile phone.
However, the video processed by the transcoding unit may not necessarily meet user requirements. For example, when a user needs to enlarge a video playback window on the user proxy, the user can only enlarge a picture on the user proxy locally, which is likely to result in symptoms such as mosaic. A conventional transcoding unit cannot dynamically adjust videos according to user requirements and operation is not flexible.